Looks like with the drop of Team Fortress 2 Free-To-Play there were a lot of questions regarding how that would affect the acquisition of the Source SDK. After a little prodding from the gaming community, it looks like Valve has decided to allow everyone free access to the SDK. Original story over at Rock, Paper, Shotgun
There's no telling quite yet what will happen to the modding community, whether we will see a rise in mods or not much change at all, but what is for sure, Valve is opening the door for modding newbies to get their hands dirty without purchasing a Valve title. One less obstacle. Another step in a positive direction.